Inflatable structure, in particular a life float

ABSTRACT

In inflatable large-size structures such as life boats it is required that an external and easily accessible gas cylinder is hose-connected with a plurality of mutually separated injection areas, because the gas medium, by evaporation and expansion, produces a substantial reduction in temperature at each injection area there will potentially exist choking ice formations. This can be counteracted by distributing the injection over more areas or spots in order to achieve a more rapid and effective transfer of heat from the surroundings for making sure that the inflation can take place in a desirably rapid manner. Conventionally this implies that the structure exhibits exposed connector hoses to the different injection spots, these hoses causing trouble in use of the structure. With the invention it has been recognized that the relevant distribution system may be arranged in the interior of the structure, whereby these troublesome exterior hoses can be entirely avoided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an inflatable structure, in particulara life float, of the type equipped with an inflation gas source,preferably a CO₂ cylinder, and, departing therefrom, a distributionchannel system for supplying the gas to a plurality of inflation inletson the packed together structure.

2. Description of Related Art

For life floats and similar equipment it is very important that theinflation can be effected quite rapidly after opening of the valve ofthe gas cylinder, and for large size structures it is, therefore, apractical necessity that the gas cylinder is connected to more inflationinlets located with noticeable mutual spacing. This requirement is owingto the fact that the associated vivid evaporation of the CO₂ liquid fromthe cylinder produces a strong cooling, whereby the product introducedinto the structure at the inflation inlets will be particles of frozenCO₂ liquid, the so-called CO₂ snow. For the desired evaporation, heatshould be conveyed from the surroundings, and if the entire amount ofinflation gas is let in at only a single inlet there will be a high riskof insufficient heat supply to that place; the inlet area may end up asone big ice lump, from which the gas will be only slowly generated. If,on the other hand, the gas liquid is supplied to several differentareas, many times more heat can then be attracted from the closesurroundings to the total amount of the supplied gas, and it is thenpractically possible to get down to the prescribed, relatively briefinflation times, e.g. three minutes for a large size life float, evenwith the use of a single gas cylinder.

On this background it is a conventional practice that the relevant unitsappear with a suitably placed gas cylinder with an easily accessiblevalve and with one or more associated hoses extending to the differentinlet places, which should be located mutually spaced by at least a halfor a whole meter. Thus, it is characteristic that the units present ahose system, which may be more or less well anchored to the inflatablestructure, but in any case reveals itself as a problematic excrescenceon the structure.

It should be mentioned that there are already known some types ofinternal distribution systems, e.g. as disclosed in U.S. Pat. No.2,993,217, which, however, act to distribute the gas which has alreadyentered the gaseous phase. In that connection it is a purpose to protectthe rubber wall against the chilling shock that may occur at theinjection area, but this does not change the fact that it is still atthis local area the whole amount of gas is brought to evaporate.

SUMMARY OF THE INVENTION

With the invention it has been recognized that a relevant inlet areashould not necessarily be a place where the injection is effected acrossan outer surface forming wall of the inflatable structure itself,inasfar as it is possible to establish an internal distribution system,such that an exteriorly placed gas cylinder, accessible for inspectionand replacement, when needed, should only be tube or hose connected withone throughlet, from which a distribution channel system may then bebranched off to extend internally in the structure, debouching at anumber of different places. For the discussed conditions with respect tothe conveying of heat from the close surroundings it is fullyunimportant whether the gas supply is effected through a conventionalinjection opening through the wall of the structure or through themouthing of a hose inside the structure. On the other hand, however, itwill be an important improvement that the outside of the structure willno longer exhibit the said disturbing excrescences which, in emergencysituations, may give rise to serious problems.

On this background it should be stressed that in connection with theinvention the relevant purpose is to distribute the liquid gas medium,i.e. with the use of relatively narrow channels or hoses just as inconnection with the known exteriorly placed distribution systems.Already in connection with a branched off hose system it will bepossible to achieve a certain evaporation of the gas medium, viz. ateach widening of the cross section of the flow, although this will beless significant as long as the actual cross sections are substantiallythe same as the one occurring at the outlet from the gas cylinder. Putanother way, by coordinating the hose diameter and the number and sizeoutlets from the hose system into the inflatable body to the size of theoutlet from the liquified inflation gas cylinder, evaporative freezingof the liquified inflation gas can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention is described in more detail withreference to the drawing, in which:

FIG. 1 is an illustration of the relevant prior art, while

FIG. 2 is a corresponding illustration of the principle of theinvention.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1 it is shown that from a gas cylinder 2 with a release valve 4there extends an external hose system 6 for conveying of the gas to moreexternally mounted inflation nozzles 8 on an inflatable structure 10.Each of these throughlets 8 are relatively costly to establish, and thehose system 6 appears as an external structure which can very easilyinterfere with details in the surroundings and thus create considerableproblems with respect to a rapid and safe release of the life savingunit.

According to the invention, FIG. 2, the gas cylinder 2, 4 is pipe orhose connected with the inflatable unit solely by a single throughletconnection 12, from which a hose system 14 extends internally in theunit 10. It may be a combination of parallel and series connections to asuitable number of internal nozzles or simple outlets 16.

By the production of the unit 10 it is quite simple to mount theinternal system 14, 16, and normally it will be sufficient to establishbut a single throughlet 12.

Optionally, instead of regular hoses 14 it is possible to make use ofsuitably heavy sheet strips 18 which, by weldings 20, are secured to aninner wall side of the unit 10 for the formation of distributionchannels. A further possibility is to make use of slit shaped inflationnozzles 22 for the gas.

What is claimed is:
 1. An inflatable structure comprising: an inflatablebody; an inflation gas source in the form of a liquified inflation gascylinder located externally of said inflatable body; and a gasdistribution system connected to said gas cylinder, said gasdistribution system including an internal pressure resistant hose systemextending internally through said inflatable body; wherein said internalpressure resistant hose system is a separate member inserted into saidinflatable body, has at least one hose with an inlet extending through awall of said inflatable body for receiving liquified inflation gas fromsaid liquified inflation gas cylinder and a plurality of outlet openingsspaced along the length of the hose for distributing liquified inflationgas into said inflatable body; and wherein said at least one hose has adiameter and said plurality of outlets have a number and size which arecoordinated to the size of an outlet from the liquified inflation gascylinder as a means for preventing an evaporative freezing of theliquified inflation gas.
 2. An inflatable structure according to claim1, wherein said internal pressure resistant hose system is connected tothe liquified inflation gas cylinder via an external hose system.
 3. Aninflatable structure according to claim 2, wherein branching connectionsof hoses have a cross section which is essentially the same as that ofan outlet connection of the liquified inflation gas cylinder to theexternal hose system.
 4. An inflatable structure according to claim 1,wherein said inflatable body is a life float.
 5. An inflatable structureaccording to claim 1, wherein said at least one hose comprises aplurality of hoses connect to a single said inlet.